Manual J results create a dilemma

[farfigngn]

Hi. Im in NY and just was given the results of the Man J. The heat required is 46K btu for my house which is 3000 sq/ft (house is pretty tight insulation wise). Unfortunately, I cant seem to find an oil boiler that is close to that small and the contractor just wants to throw in the smallest he can find which is 74k btu. Gas is not available in my area. I was told I could go with 74k btu and have a smaller nozzle installed? Is that an option or will I have problems with that option? I dont want the boiler to short cycle either because it is much larger than required? Are there any reliable oil boilers that small? Thanks.

[beenthere]

Doubt you'll find anything really smaller.

[farfigngn]

Will that nozzle mod work or am I asking for trouble?

[beenthere]

You can only decrease so much. And then you lose efficiency.

What kind of hot water heat, radiant, baseboard, hydro coil, etc?

[dijit]

You could always just open a window.:grin2:

[farfigngn]

I have Hydro-air and I would prefer not to open a window. lol I heard that I could reduce by 10% with smaller nozzle. Is that true? Any other manufacturers that might have anything smaller?

[kenney t]

how about a small three pass design?

[beenthere]

If not done right. That 10% reduction in nozzle size can cost you a lot in excess oil use, and in increased cost of cleaning the boiler.

What brand and model boiler was quoted to you.

[heaterman]

That's an impressively low btu requirement for a 3000 sq ft home in NY. Maybe an oil fired hot water heater instead. Did run across one rated at 48,000 I.B.R. btus with an afue rating of 87.5%

[farfigngn]

The boiler that was spec'd for the house was the Burnham mpo-iq. Smallest unit is about 74k btu net I believe iq-84. I was looking at the Biasi B-3 which I think is 58k gross. Also, If I do get a boiler that is smaller will my 50 gal amtrol indirect water tank recover fast enough?

[mchild]

Hi. Im in NY and just was given the results of the Man J. The heat required is 46K btu for my house which is 3000 sq/ft (house is pretty tight insulation wise). Unfortunately, I cant seem to find an oil boiler that is close to that small and the contractor just wants to throw in the smallest he can find which is 74k btu. Gas is not available in my area. I was told I could go with 74k btu and have a smaller nozzle installed? Is that an option or will I have problems with that option? I dont want the boiler to short cycle either because it is much larger than required? Are there any reliable oil boilers that small? Thanks.


First thing I would do is check and double check that Man J and make sure it is as accurate as possible. If you find that it is correct you may then want to find installers in your area are familiar with the Baisi 3-pass line. They have a small boiler that has a 58K IBR rating with 87% AFUE rating.

http://www.qhtinc.com/pdf/b10final.pdf

[beenthere]

Also, If I do get a boiler that is smaller will my 50 gal amtrol indirect water tank recover fast enough?

Fast enough for what?

For average shower use, or to fill a hot tub.

A hot tub, no.

[Snoring Beagle]

That's an impressively low btu requirement for a 3000 sq ft home in NY. Maybe an oil fired hot water heater instead. Did run across one rated at 48,000 I.B.R. btus with an afue rating of 87.5%



Why not? I like that idea too.

http://www.bockwaterheaters.com/Products/Product_pdfs/80035_SpacSavr_09-07.pdf

[tpa-fl]

You could always just open a window.:grin2:

That is the tried & true method of heat regulation in many buildings of NYC. :)

[farfigngn]

That all sounds good. I'm trying to compare 3 units, Biasi B-3 and the MPO iq-84. The Buderus G125/21 looks great but might be cost prohibitive. What exactly am I looking at when I match up the total 46k btu heat loss value with. Is it the DOE, IBR, Net output, or Gross output? I forgot to mention the contractor recommended tempering the garage with Modine hot water type blower (we have bedrooms above the garage). Would that change the requirements for size?

[beenthere]

It does if it wasn't included in the heat loss calc.

Use IBR